Technological improvements in processing speed and power and in memory capacity have opened the door to handheld electronic devices that provide a variety of functions that were heretofore found only in larger and bulkier devices. For instance, manufacturers have been able to shrink the size of a mobile phone to fit in the palm of a user's hand.
While smaller devices are generally perceived to be desirable, a problem arises when the space for physical features of the device diminishes. For example, in most cases, a mobile phone has a minimum number of alphanumeric keys, and additional input keys, e.g., navigation and select keys. These keys are typically located on one face of the device, which also typically includes a display, e.g., an LCD, so that the user can see what he or she has entered, or so that the user can access other functions of the device.
To make room for the input keys and display on the device face, the size of the keys and/or display, and the spacing between keys is usually decreased. Nevertheless, because the keys are so small and the number so many, it becomes difficult to distinguish between the keys. Moreover, even if the user can make such a distinction, it is difficult to press the desired key because the space between keys is so small. For individuals with large fingers, this can be particularly frustrating.
To address this problem, some devices place direction related keys, i.e., navigation keys, on a side surface perpendicular to the device face. Nevertheless, because these handheld electronic devices are slim devices, the side surface is thin and the keys must be positioned in a row along the side surface. Accordingly, navigation keys assigned to allow the user to navigate in a direction perpendicular to the row, i.e., right or left if the keys are on the left or right side of the device, are not intuitive for the user. Other devices offer a touchpad on a backside of the device, i.e., on the surface opposing the device face. (See, e.g., U. S. Pat. No. 5,543,588, entitled “Touch Pad Driven Handheld Computing Device” issued Aug. 6, 1996 to Bisset et al.). Here, the user navigates by tracing his or her finger on the surface of the touchpad to control the movement of a cursor on the display. Nevertheless, compared to input keys, a touchpad is more expensive, consumes more power, and requires more complex programming.
Each of the above described devices presents an additional disadvantage as well. For each device, the location of the navigation mechanism is fixed. Thus, if the user is not comfortable having the navigation mechanism facing away from him or her as the user is viewing the display, the user cannot change the position of the navigation mechanism.
Accordingly, a need exists for a system and method that provides navigation mechanisms, such as input keys, on a handheld electronic device. The system and method should be highly intuitive for the user, while being cost effective and efficient. The present invention addresses such a need.